ar X iv : a st ro - p h / 05 07 14 5 v 1 6 J ul 2 00 5 X - ray Pulsations in the Supersoft X - ray Binary CAL 83

ar X iv : a st ro - p h / 06 05 39 7 v 1 16 M ay 2 00 6 An Investigation of Be / X - ray Pulsars with OGLE - III Data

Received ; accepted – 2 – ABSTRACT We have studied five seasons of OGLE-III data for eight SMC Be/X-ray pulsars for which no other survey data were available. We have determined orbital periods for four of these binary systems, one of which also shows nonradial pulsations. Optical identification of SMC X-2 is reconsidered, but no periods were found for either of the two possible candidates.

X-ray Pulsations in the Supersoft X-ray Binary Cal 83

Received ; accepted – 2 – ABSTRACT Chandra and XMM-Newton X-ray data reveal that the supersoft X-ray binary CAL 83 exhibits 38.4-minute pulsations at some epochs. These X-ray variations are similar to those found in some novae and are likely to be caused by nonradial pulsations of the white dwarf. This is the first detection of pulsations in a classical supersoft X-ray binary.

ar X iv : a st ro - p h / 05 10 48 3 v 1 1 7 O ct 2 00 5 Discovery of the Millisecond X - Ray Pulsar HETE J 1900 . 1 - 2455

We report the discovery of millisecond pulsations from the low-mass X-ray binary HETE J1900.1-2455 which was discovered by the detection of a type I X-ray burst by the High Energy Transient Explorer 2 (HETE-2). The neutron star emits coherent pulsations at 377.3 Hz and is in an 83.3 minute circular orbit with a companion with a mass greater than 0.016 M ⊙ and likely less than 0.07 M ⊙. The comp...

ar X iv : a st ro - p h / 05 07 06 6 v 1 4 J ul 2 00 5 Multiband Echo Tomography of Sco X - 1

ar X iv : a st ro - p h / 00 07 10 5 v 1 8 J ul 2 00 0 THE BROAD BAND SPECTRUM AND VARIABILITY OF SEYFERT 1

Recent results on the X–ray spectrum and variability of Seyfert 1 galaxies are reviewed. New spectral results from BeppoSAX observations are also presented and briefly discussed.